It has previously been proposed to detect certain types of mechanical problem by sensing distinctive sounds that they produce, especially ultrasonic sounds. For example, a fluid leak from a pressurized system can produce a hissing sound, and a failing bearing can produce a grinding sound. In order to detect ultrasonic sound, it is necessary for the sound to be fed to a transducer that will convert it to frequencies that are audible to the human operative. When inspecting machinery, this typically involves a handheld device containing the transducer, and having at its front end a probe that can be placed near to, or in contact with, the machinery that is to be inspected.
Different probes are usually preferred for contact with the machinery and for air pickup near the machinery. A contact probe is typically a solid rod of material that transmits the ultrasonic frequencies of interest. An air probe is typically a tube that guides the sound in air to the transducer, while excluding extraneous noises.
Detectors with interchangeable probes have previously been proposed. One example of such a detector is sold by the assignees of the present application under the trademark Spectroline® Marksman II. A disadvantage of most detectors with interchangeable probes is that a separate carrying case is necessary to contain the detector and the various probes. That can be inconvenient when working in the field, because the operative may want to change from one probe to the other in places where it is inconvenient to bring the carrying case or to set down the carrying case in order to take out one probe and put away another probe.
There is, therefore, a need for a more compact and portable handheld ultrasonic detector.